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Leetcode
Easy
Trees
Recursion
Path Sum
Determine whether a binary tree contains a root-to-leaf path whose node values add up to a target sum.
Acceptance 0%
Problem Statement
Given the root of a binary tree and an integer targetSum, determine whether the tree has at least one root-to-leaf path such that the sum of the node values along that path equals targetSum.
A path must start at the root and end at a leaf. A leaf is a node with no children.
Input Format
- A binary tree root
root - An integer
targetSum
Output Format
- Return
trueif there exists at least one root-to-leaf path whose values sum totargetSum. - Otherwise, return
false.
Constraints
- The tree may be empty.
- Node values and
targetSumare integers. - The answer depends only on root-to-leaf paths, not any downward path.
Examples
Sample cases returned by the problem API.
Example 1
Input
root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22
Output
true
Explanation
One valid path is 5 → 4 → 11 → 2, and its sum is 22.
Example 2
Input
root = [1,2,3], targetSum = 5
Output
false
Explanation
The root-to-leaf paths are 1 → 2 and 1 → 3, with sums 3 and 4.
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